1. Technical Field
The present invention relates generally to furnace and chemical vessel doors, and more particularly to a fill door having an angled movement.
2. Background Art
Furnace and chemical vessel fill doors are frequently set on an angled surface on a furnace or vessel shell. Positioning the door on an angled surface facilitates loading and transferring molten materials and dangerous chemicals. However, this positioning also makes manual movement of heavy doors difficult and occasionally impossible. It has been proposed to provide mechanical means, e.g., hydraulic or pneumatic, to assist in the door movement. This solution is needlessly costly and ultimately impracticable.
Furnace door designs generally are generally adapted for side wall positioning and address the need for thermal and gas tight fitting, while preferring mechanical operation. Recent examples include U.S. Pat. No. 4,883,002 to Schuster, which discloses a furnace closing mechanism for industrial furnaces composed of a furnace door latched to the furnace shell and a heat-insulating door fastened to inner side of the furnace door. The door is coupled to the door frame and furnace shell with a bayonet-type joint.
U.S. Pat. No. 5,727,479 to McAfee, et al., teaches an improved guillotine-style door closure system for a furnace that comprises an opening on the vertical side of a furnace, and a furnace door adapted to mate with the frame. The apparatus purportedly provides a uniform sealing forces along the entire door frame and prohibits the escape of gases between the seal and further prevents the crushing of ceramic fibers used for lining the doors.
The fill door of the present invention represents a solution to the above-described problem. The present invention comprises a center floating door on an angled hinge that allows the door to be opened and closed manually with very little effort and to be sealed after closing.
Many furnace designs include angled walls, and due to the advantages of this design it is desirable to fashion liquid-containing vessels similarly. However, to date doors for furnaces and vessels have developed for use on vertical and horizontal surfaces and to provide vertical and horizontal closures. When the door is heavy, because of the need for a thermal and gas tight closure, vertical and horizontal door motions (which require some measure of lifting and holding of the door) can become difficult and necessitate mechanical assistance.
Accordingly, there remains a need for a fill door having an angled movement, such that the door can be positioned on an opening on an angled surface while yet providing substantially level horizontal movement of the door.
The present invention is a fill door adapted for use on the angled surfaces of furnace shells or chemical containers. The door is pivotally coupled to a door frame which is integral with the angled surface. The frame includes a rim surrounding a furnace opening and mates with a female channel in the door. A U-shaped bracket latch is pivotally connected to the frame. The latch includes a threaded spindle operatively connected to a crank. The surface of the door includes a female sleeve which has a bore for accommodating the end of the spindle when the latch is over the door and the spindle is tightened into its closed and locked position. The door further includes a cantilevered arm having an angled bore which allows it to swivel around a substantially vertical cylindrical post connected to frame. The arm and thus the door swings in a substantially horizontal plane (i.e., a plane substantially 90 degrees relative to the axis of the post).